Modified toggle assembly for circuit breakers

ABSTRACT

An electromagnetic circuit breaker for opening a set of contacts upon the occurrence of predetermined conditions, having an automatically resettable linkage mechanism. The linkage mechanism includes a toggle assembly having a latch which is biased to the latching position and whose movement to the latching position is stopped by the pin which connects the two links of the toggle assembly to each other.

United States Patent lnventor Ronald Nicol Trenton, NJ.

Appl. NO. 16,526

Filed Mar. 4, 1970 Patented Aug. 24, 1971 Assignee Heinemann Electric Company Trenton, NJ.

MODIFIED TOGGLE ASSEMBLY FOR CIRCUIT BREAKERS 4 Claims, 8 Drawing Figs.

us. C l 335/167, 335/26 Int. Cl I-IOlh 9/20 Field olSearch 335/167,

[56]- References Cited UNITED STATES PATENTS 3,329,913 7/1967 Camp 335/174 Primary Examiner-Harold Broome 'An0rney-Denny & Denny ABSTRACT: An electromagnetic circuit breaker for opening a set of-contacts upon the occurrence of predetermined conditions, having an automatically resettable linkage mechanism. The linkage mechanism includes a toggle assembly having a latch which is biased to the latching position and whose movement to the latching position is stopped by the pin which connects the two links of the toggle assembly to each other.

PATENTED M1524 l9?! 3.601126 sum 1 OF 3 RONALD mco 8Y MODIFIED TOGGLE ASSEMBLY FOR CIRCUIT BREAKERS BACKGROUND OF THE INVENTION This invention pertains generally to electric circuit breakers of the type having an electromagnetic tripping device and a linkage mechanism which includes an overcenter, automatically resettable toggle assembly. More particularly, the invention provides a modified latch for latching the two links of the toggle-assembly. A circuit breaker of the type to which this invention relates is shown in U.S. Pat. No. 3,329,913 and in US. Patent application Ser. No. l6,5 l 8 filed Mar. 4, 1970.

BRIEF SUMMARY OF THE INVENTION It is an object of the invention to simplify the arrangement by which the limiting movement of the latch to the latching position is determined.

The circuit breaker comprises a suitable housing and an automatically resettable linkagemechanism having a movable arm carrying a movable contact. A stationary contact is mounted within the housing and is carried by a first terminal. The stationary contact is engageable by the movable contact and an electromagnetic device is provided for tripping the linkage mechanism on predetermined overloads. The electromagnetic device includes a coil connected at one end to the movable arm and at the other end to a second terminal.

The linkage mechanism includes a toggle assembly comprising a catch link pivotally connected to a carrier link by a pin and a latch carried by the carrier link to latch the links in an overcenter toggle position. The latch comprises a lock shaft and a drive link. 7

The drive link has an arm (at one side of the lock shaft) to be tripped by the electromagnetic device and an extension (on the other side of the lock shaft) which engages the pin to limit movement of the latch. A latch reset coil spring biases the lock shaft into latching engagement with the catch link and also biases the extension into engagement with the pin.

I BRIEF DESCRIPTION OF THE VIEWS FIG. I is a side elevation showing a circuit breaker with an inner half-case removed and the outer housing cut away to expose the operating mechanism with the contacts in the open position; a 2

FIG. 2 is a side elevation similar to FIG. 1, but showing the operating mechanism of the circuit breaker in the contacts closed position;

FIG. 3 is an enlarged, side I elevation of the toggle mechanism illustrated in FIGS. 1 and 2, illustrating the latched position thereof;

FIG. 4 is an end view of the toggle mechanism shown in FIG. 3 taken from the left side in FIG. 3;

FIG. 5 is an enlarged, perspective view of the latch of the toggle assembly shown in FIGS. 1 to 4;

FIG. 6 is an enlarged partial, sectional view of the toggle assembly and is taken along the line 66 in FIG. 4, showing the catch link latched with the lock shaft;

FIG. 7 is an enlarged partial, sectional view of the toggle assembly and is taken along the line 7-7 in FIG. 4; and

FIG. 8 is an enlarged partial view of the pin connecting the catch and carrier links and is taken along the line 88 in FIG. 3.

DETAILED DESCRIPTION Referring to the drawings, the circuit breaker 10 comprises a housing which may be formed by an outer case 11 and an inner case 12, the latter being preferably molded from a plastic material and divided into two juxtaposed, approximately half-cases 14 only one of which is illustrated in FIGS. 1 and 2. The circuit breaker 10 includes an automatically resettable linkage mechanism 18 which is mounted within and enclosed by the case I2, but for a part ofa handle 19 which extends out of the case 12, as shown.

The linkage mechanism 18 comprises a movable contact 20 contact 22, the latter being carried by a stem 23 forming part of a terminal 24. The movable arm 21 is connected by a flexible conductor 26 to one end of a coil 30 forming part of an electromagnetic device 32 which is also enclosed by the housing 15 and which is associated with the linkage mechanism 18 to trip open the contacts on predetermined overloads. The electrical circuit of the circuit breaker is completed by connecting the other end of the coil 30 toa terminal 36. As shown, the terminals 24 and 36 are carried by a plate 37 forming part of the outer case 1 I and extend outwardly therefrom.

Further, the movable arm 21 is biased by a spring 38 toward the open position of the contacts 20 and 22 and the movable arm 21 is mounted on a pin 39 about which it pivots, the pin 39 having end portions carried by two spaced plates 34 only one of the plates being shown in FIG. 1. In FIG. 2, the plate 34 closest to the viewer has been partially cut away for illustrative purposes.

The movable arm 21 is also connected by a pin 42 to a toggle assembly 44, the latter being in turn connected to a handle link 45 by a pin 46. The handle link 45 pivots about a pin 47 having end portions also carried by the spaced frame plates The end portions of the pin 42 limit opening movement of the arm 21 by abutting with the two spaced frame plates 34.

The frame plates 34 are integral with an L-shaped magnetizable frame 52 comprising a horizontal leg 53 and a vertical leg 54. The frame 52 forms part of the electromagnetic device 32 to which is secured a time-delay tube 48 housing a spring-biased magnetizable core (not illustrated) movable against the retarding action of a suitable fluid to provide a time delay before tripping of the linkage mechanism 18 at certain overloads. As illustrated, the horizontal frame leg 53 also carries the coil 30, the latter comprising an insulator spool or bobbin and multiple turns of insulated wire, not shown in detail.

The operation of this type of linkage mechanism 18 and electromagnetic device 32 is generally set forth in US. Pat. No. 2,360,922, among others, but for claritys sake may be briefly described as followswhen the handle 19 is rotated counterclockwise, as viewed in FIG. 1, the toggle assembly 44 and the movable arm 21 all move down, against the bias of the spring 38, and move the contact 20 into engagement with the contact 22, the contacts assuming the closed position which is illustrated in FIG. 2.

Upon the occurrence of a predetermined overload condition, assuming the circuit breaker to be in the contacts closed position, FIG. 2, the armature 55 (which is also part of the electromagnetic device 32) is attracted toward the pole piece 56 either after a time-delay period or virtually instantaneously, depending on the overload current. The armature 55 pivots toward the pole piece 56, about a pin 57 whose end portions are also carried by the spaced frame plates 34, causing the oppositely extending trip member 58 (which is integral with the armature 55) to pivot to the right and to trip the arm 124 forming part of a latch assembly 62 which, when the toggle assembly 44 has been moved to the contacts closed position, is juxtaposed with the armature trip member 58 (as shown in FIG. 2), whereupon the toggle assembly 44 collapses 7 under the pressure of the opening spring 38.

To minimize and/or extinguish any are that may form between the contacts 20 and 22 whenever the contacts are opened, assuming the circuit breaker to be energized, a stacked array of three magnetizable, metal grids 70, 71 and 72 may be supported within the inner case 12 in association with the contacts 20 and 22.

The handle 19 further includes a forked lower end 81 engaging a shaft 82 carried by the handle link 45. The pin 47 carries a coil torsion spring 84 on each side of the handle link 45 positioned between the adjacent frame plate 34 and the handle link45. Each spring 84 has one end bent and hooked around one of the frame plates 34 and the other end engaging a projection on the side of the handle link 45 so as to bias,

through the handle link 45, the handle 19 clockwise and toward the contacts open position, as illustrated in FIG. 1.

The toggle assembly 44 comprises a catch link 86 and a carrier link 88 pivotally connected to each other by a pin 90. After tripping of the latch assembly 62 by the armature 55, the handle spring 84 automatically relatches the toggle assembly links 86 and 88 in the overcenter position shown in FIGS. 1, 3 and 6 and automatically moves the handle 19 to the contacts open position.

The catch link 86 and the carrier link 88 comprise the two toggle links of the toggle assembly 44 and are pivotally connected together by the pin 90 having an enlarged head 100 and a shank 102, FIG. 8, the end of the shank 102 opposite to the head 100 being peened over to pivotally secure the links 86 and 88 together, FIG. 4. The carrier link 88 comprises two legs 91 and 92, FIG. 4, bridged by an arm 93, FIGS. 3 and 6.

The carrier link 88 supports the latch assembly 62 which includes a drive link 104 and a lock shaft 106. The lock shaft 106 has a half-moonlike central portion 108 between the two legs 91 and 92 of the carrier link 88, the half moon 108 being engaged by a tooth 110 formed on the catch link 86.

The drive link 104 is initially separate from the lock shaft. The lock shaft 106 has a left-hand end 112, of smaller diameter than the remainder. The left-hand end 112 is pressed into a hole in the drive link 104 and peened over to secure the lock shaft 106 to the drive link 104.

The drive link 104 includes an arm 124 having a column 129 engageable by the armature trip member 58 to trip the linkage mechanism on predetermined electrical conditions and an extension.126 abuttable with the head 100. As illustrated, the arm 124 extends to one side of the lock shaft 106 and the extension 126 extends on the other side.

Coiled about the cylindrical land 1 14 of the lock shaft 106 is a coil spring 120, disposed between the leg 92 and the drive link 104, FIG. 4, the spring 120 having an end portion 122 hooked over the extension 126 and the other end portion 128, FIG. 7, resting against the shank 102 between the head 100 and the adjacent leg 92 of the carrier link 88, the spring 120 being stressed at all times so as to bias the latch assembly 62 clockwise, as viewed in FIG. 3, tending to always bring the half moon 108 into engagement with the tooth 110 of the catch link 86 and the extension 126 into engagement with the head 100, and biasing the latch assembly 62 axially to the right, as viewed in FIG. 4.

The column 129 projects at right angles to the plane in which moves the armature trip member 58 for engagement therewith upon the occurrence of predetermined overloads to collapse the linkagemechanism l8 and open the contacts 20 and 22.

The extension 126 has an integral arcuate portion 130 overhanging the spring 120, as shown in FIG. 4, on the right-hand side of the central section, which tends to balance the latch assembly 62 about the longitudinal axis of the lock shaft 106.

The lock shaft 106 is mounted by the aforementioned circular land 114 and by a right-hand land 132, FIG. 5, in aligned holes in the legs 91 and 92 of the carrier link 88 and would be freely movable axially but for the part of the catch link 86 which is received at all times between the opposed walls forming the slot 140, FIG. 5, at the half moon surface 108 and which prevents such free movement.

Referring to FIGS. 2 and 3, clockwise movement of the latch assembly 62 is limited by abutment of the extension 126 with the head 100, as mentioned previously. Counterclockwise movement of the lock assembly 62 is restrained by the coil torsion spring 120. The armature trip member 58 moves the column 129 sufficiently to trip the toggle assembly 44 and collapse the links 86 and 88 without requiring counterclockwise movement of the latch assembly 62 to abut any stop member.

Having described the invention, what I claim is:

1. In a circuit breaker comprising a housing, an automatically resettable linkage mechanism enclosed by said housing but for a part of a handle means which extends through said housing, said mechanism including a movable arm carrying a movable contact, a stationary contact mounted within said housing and carried by a first terminal, said stationary contact being engageable by said movable contact, an electromagnetic device for tripping said linkage mechanism on predetermined overloads, said electromagnetic device including a coil connected at one end to said movable arm and at the other end to a second terminal, said electromagnetic device having a magnetizable frame forming spaced first and second plates which carry said linkage mechanism, said linkage mechanism including a toggle assembly comprising a catch link, a carrier link and a pivotally mounted latch carried by said carrier link to latch said links in an overcenter toggle position, a pin pivotally connecting said catch andcarrier links, the improved latch comprising a lock shaft and a drive link, said drive link having an arm at one end and an extension at the other end, said arm being tripped by said electromagnetic device upon the occurrence of predetermined overloads, a latch reset coil spring biasing said lock shaft into latching engagement with said catch link, said latch reset coil spring being carried by said lock shaft between said drive link and said carrier link, engagement of said extension with said pin limiting movement of said latch toward the latching position, said latch reset coil spring having one end hooked onto said drive link and the other engaging said pin.

2. The structure recited in claim 1 wherein said pin has an enlarged'head and a shank portion extending through said catch and carrier link to pivotally connect said links to each other. I

3. The structure recited in claim 2 wherein said head is spaced from said carrier link and an end portion of said spring is received between said head and said carrier link.

4. In a circuit breaker comprising a housing, an automatically resettable linkage mechanism enclosed by said housing but for a part of a handle which extends through said housing, said mechanism including a movable arm carrying a movable contact, a stationary contact mounted within said housing and carried by a first terminal, said stationary contact being engageable by said movable contact, an electromagnetic device for tripping said linkage mechanism on predetermined overloads, said electromagnetic device including a coil connected at one end to said movable arm and at the other end to a second terminal, said electromagnetic device having a magnetizable frame which carries said linkage mechanism, said linkage mechanism including a toggle assembly comprising a catch link, a carrier link and a pivotally mounted latch assembly carried by said carrier link to latch said links in an overcenter toggle position, a pin ,pivotally connecting said catch and carrier links to each other, the improved latch assembly comprising a lock shaft and a drive link, said drive link having an arm at one end and an extension at the other end, said arm being tripped by said electromagnetic device upon the occurrence of predetermined overloads, spring means biasing said lock shaft into latching engagement with said catch link and biasing said extension toward said pin, said spring means being carried by said lock shaft, and said engagement of said extension with said pin limiting movement of said latch toward the latching position. I 

1. In a circuit breaker comprising a housing, an automatically resettable linkage mechanism enclosed by said housing but for a part of a handle means which extends through said housing, said mechanism including a movable arm carrying a movable contact, a stationary contact mounted within said housing and carried by a first terminal, said stationary contact being engageable by said movable contact, an electromagnetic device for tripping said linkage mechanism on predetermined overloads, said electromagnetic device including a coil connected at one end to said movable arm and at the other end to a second terminal, said electromagnetic device having a magnetizable frame forming spaced first and second plates which carry said linkage mechanism, said linkage mechanism including a toggle assembly comprising a catch link, a carrier link and a pivotally mounted latch carried by said carrier link to latch said links in an overcenter toggle position, a pin pivotally connecting said catch and carrier links, the improved latch comprising a lock shaft and a drive link, said drive link having an arm at one end and an extension at the other end, said arm being tripped by said electromagnetic device upon the occurrence of predetermined overloads, a latch reset coil spring biasing said lock shaft into latching engagement with said catch link, said latch reset coil spring being carried by said lock shaft between said drive link and said carrier link, engagement of said extension with said pin limiting movement of said latch toward the latching position, said latch reset coil spring having one end hooked onto said drive link and the other engaging said pin.
 2. The structure recited in claim 1 wherein said pin has an enlarged head and a shank portion extending through said catch and carrier link to pivotally connect said links to each other.
 3. The structure recited in claim 2 wherein said head is spaced from said carrier link and an end portion of said spring is received between said head and said carrier link.
 4. In a circuit breaker comprising a housing, an automatically resettable linkage mechanism enclosed by said housing but for a part of a handle which extends through said housing, said mechanism including a movable arm carrying a movable contact, a stationary contact mounted within said housing and carried by a first terminal, said stationary contact being engageable by said movable contact, an electromagnetic device for tripping said linkage mechanism on predetermined overloads, said electromagnetic device including a coil connected at one end to said movable arm and at the other end to a second terminal, said electromagnetic device having a magnetizable frame which carries said linkage mechanism, said linkage mechanism including a toggle assembly comprising a catch link, a carrier link and a pivotally mounted latch assembly carried by said carrier link to latch said links in an overcenter toggle position, a pin pivotally connecting said catch and carrier links to each other, the improved latch assembly comprising a lock shaft and a drive link, said drive link having an arm at one end and an extension at the other end, said arm being tripped by said electromagnetic device upon the occurrence of predetermined overloads, spring means biasing said lock shaft into latching engagement with said catch link and biasing said extension toward said pin, said Spring means being carried by said lock shaft, and said engagement of said extension with said pin limiting movement of said latch toward the latching position. 